(1) Field of the Invention
The present invention relates to a grout composition incorporating a polymer containing aluminum and one or more calcium compounds as gas forming and expansible additives which are admixed with Portland cement, and optionally sand. In particular, the present invention relates to the use of selected automotive paint sludge powders in the grout composition.
(2) Descriptions of Related Art
Grout is generally a mixture of sand and Portland cement which meets certain specifications, although for limited applications it can be prepared without sand as a filler. Non-shrink grouts are dimensionally stable and are used in applications such as: (1) precision grouting of machinery bases; (2) structural grouting of precast columns, steel columns, crane rails, precast beams, and the like; and (3) enclosing guard rails, sign posts, bridge seats, anchor bolts, guide rails, dowels, etc. Dimensional stability over time is a key requirement for non-shrink grout (ASTM C 1107 & CRD-C6 21) (ASTM C1107-91a, "Standard Specifications for Packaged Dry, Hydraulic Cement Grout (Non-Shrink)," (1991); and CRD-C 621-82B, "Corps of Engineers Specifications for Non-shrinkage Grout," (1982)).
Moisture loss from fresh and hardened cement-based grout leads to plastic (settlement) and drying shrinkage movements, respectively (Mehta, P. K., et al., "Concrete Structure, Properties and Materials," Prentice Hall, Inc. 548 (1993)). In order to produce expansive tendencies to overcome shrinkage in fresh grout, the prior art has resorted to gas production or expansion associated with the rusting of iron powders in grout (U.S. Grout Corporation, "Grouting Handbook," 200 (1983)). Fresh grout is grout which has not yet hardened and thus can expand. Hardened grout can expand as described in application Serial No. 08/142,610, now abandoned. In hardened grout, expansion is also produced through promoting expansive reactions (Mehta, P. K., et al., "Concrete Structure, Properties and Materials," Prentice Hall, Inc. 548 (1993)).
A process for producing dry powders from overspray in painting of various products, particularly vehicles, is described in Environmental Information 13 to 17 (May 1992). This publication suggests using the powder in cement blocks on roofing mastics essentially as an inert filler. There was no suggestion that such paint powders could be used for a grout. The drying process for the powder includes a heated screw conveyor which dries the powder. Volatile organic compounds are removed from the dried paint along with water during the drying. The process and apparatus is disclosed in U.S. Pat. No. 4,750,274 and U.S. Pat. No. 4,980,030.
Numerous polymer compositions have been suggested for use in concrete as inert fillers. Such uses of polymers are taught by Japanese Patent No. 60033276 (Abstract; 1985), for instance where foamed styrene is used for paver stones. Numerous other patents describe polymer powders used as fillers. These polymers are essentially insert and do not cause the concrete to expand.
There is a need for improved non-shrink grout compositions. There is particularly a need for grout compositions which are reliable and inexpensive.